Acute lung injury from mechanical ventilation at moderately high airway pressures

1990 ◽  
Vol 69 (3) ◽  
pp. 956-961 ◽  
Author(s):  
K. Tsuno ◽  
P. Prato ◽  
T. Kolobow
Keyword(s):  
Mechanical Ventilation ◽  
Peak Inspiratory Pressure ◽  
Blood Gases ◽  
Inspiratory Pressure ◽  
Control Group ◽  
Arterial Blood Gases ◽  
Lung Weight ◽  
Pulmonary Atelectasis ◽  
Arterial Pco2 ◽  
Arterial Blood

We have explored adverse pulmonary effects of mechanical ventilation at a peak inspiratory pressure of 30 cmH2O in paralyzed and anesthetized healthy sheep. A control group of eight sheep (group A) was mechanically ventilated with 40% oxygen at a tidal volume of 10 ml/kg, a frequency of 15 breaths/min, a peak inspiratory pressure less than 18 cmH2O, and a positive end-expiratory pressure of 3-5 cmH2O. During the ensuing 48 h, there were no measurable deleterious changes in lung function or arterial blood gases. Another 19 sheep were ventilated with 40% oxygen at a peak inspiratory pressure of 30 cmH2O under a different set of conditions and were randomly assigned to two groups. In group B, the respiratory rate was kept near 4 breaths/min to keep arterial PCO2 in the normal range; in group C, the frequency was kept near 15 breaths/min by including a variable dead space in the ventilator circuit to keep arterial PCO2 near baseline values. There was a progressive deterioration in total static lung compliance, functional residual capacity, and arterial blood gases. After some hours, there were abnormal chest roentgenographic changes. At time of death we found severe pulmonary atelectasis, increased wet lung weight, and an increase in the minimum surface tension of saline lung lavage fluid.

scholarly journals Pathophysiology and clinical consequences of arterial blood gases and pH after cardiac arrest

2020 ◽  
Vol 8 (S1) ◽  
Author(s):  
Chiara Robba ◽  
Dorota Siwicka-Gieroba ◽  
Andras Sikter ◽  
Denise Battaglini ◽  
Wojciech Dąbrowski ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Mechanical Ventilation ◽  
Cardiac Arrest ◽  
Oxygen Demand ◽  
Blood Gases ◽  
Metabolic Energy ◽  
High Morbidity ◽  
Arterial Blood Gases ◽  
Arterial Blood ◽  
Clinical Consequences

AbstractPost cardiac arrest syndrome is associated with high morbidity and mortality, which is related not only to a poor neurological outcome but also to respiratory and cardiovascular dysfunctions. The control of gas exchange, and in particular oxygenation and carbon dioxide levels, is fundamental in mechanically ventilated patients after resuscitation, as arterial blood gases derangement might have important effects on the cerebral blood flow and systemic physiology.In particular, the pathophysiological role of carbon dioxide (CO2) levels is strongly underestimated, as its alterations quickly affect also the changes of intracellular pH, and consequently influence metabolic energy and oxygen demand. Hypo/hypercapnia, as well as mechanical ventilation during and after resuscitation, can affect CO2 levels and trigger a dangerous pathophysiological vicious circle related to the relationship between pH, cellular demand, and catecholamine levels. The developing hypocapnia can nullify the beneficial effects of the hypothermia. The aim of this review was to describe the pathophysiology and clinical consequences of arterial blood gases and pH after cardiac arrest.According to our findings, the optimal ventilator strategies in post cardiac arrest patients are not fully understood, and oxygen and carbon dioxide targets should take in consideration a complex pattern of pathophysiological factors. Further studies are warranted to define the optimal settings of mechanical ventilation in patients after cardiac arrest.

Anesthetic effects on liver and muscle glycogen concentrations: rest and postexercise

1989 ◽  
Vol 66 (6) ◽  
pp. 2895-2900 ◽  
Author(s):  
T. I. Musch ◽  
B. S. Warfel ◽  
R. L. Moore ◽  
D. R. Larach
Keyword(s):  
Skeletal Muscles ◽  
Respiratory Acidosis ◽  
Blood Gases ◽  
Arterial Blood Gases ◽  
Acid Base ◽  
Arterial Lactate ◽  
Arterial Pco2 ◽  
Arterial Blood ◽  
Acid Base Status ◽  
Gastrocnemius Muscles

We compared the effects of three different anesthetics (halothane, ketamine-xylazine, and diethyl ether) on arterial blood gases, acid-base status, and tissue glycogen concentrations in rats subjected to 20 min of rest or treadmill exercise (10% grade, 28 m/min). Results demonstrated that exercise produced significant increases in arterial lactate concentrations along with reductions in arterial Pco2 (PaCO2) and bicarbonate concentrations in all rats compared with resting values. Furthermore, exercise produced significant reductions in the glycogen concentrations in the liver and soleus and plantaris muscles, whereas the glycogen concentrations found in the diaphragm and white gastrocnemius muscles were similar to those found at rest. Rats that received halothane and ketamine-xylazine anesthesia demonstrated an increase in Paco2 and a respiratory acidosis compared with rats that received either anesthesia. These differences in arterial blood gases and acid-base status did not appear to have any effect on tissue glycogen concentrations, because the glycogen contents found in liver and different skeletal muscles were similar to one another cross all three anesthetic groups. These data suggest that even though halothane and ketamine-xylazine anesthesia will produce a significant amount of ventilatory depression in the rat, both anesthetics may be used in studies where changes in tissue glycogen concentrations are being measured and where adequate general anesthesia is required.

scholarly journals Subarachnoidally administered hyperbaric morphine, buprenorphine, methadone, and 10% dextrose on cardiopulmonary function and behavior in horses

2006 ◽  
Vol 36 (5) ◽  
pp. 1444-1449
Author(s):  
Cláudio Corrêa Natalini ◽  
Renata Lehn Linardi ◽  
Alexandre da Silva Polydoro
Keyword(s):  
Blood Pressure ◽  
Body Temperature ◽  
Respiratory Rate ◽  
Motor Impairment ◽  
Blood Gases ◽  
Behavioral Changes ◽  
Control Group ◽  
Arterial Blood Gases ◽  
Arterial Blood ◽  
And Behavior

The study was done to compare the heart rate, arterial blood pressure, arterial blood gases, respiratory rate, body temperature, and behavior after subarachnoid administration of hyperbaric morphine (MorphineD10), buprenorphine (BuprenorphineD10), methadone (Methadone D10), and 10% dextrose (D10) in conscious horses. Six adult horses were studied. Treatments were administered into the lombo-sacral subarachnoid space through an epidural catheter, MorphineD10 at 0.01mg kg-1, BuprenorphineD10 at 0.001mg kg-1, MethadoneD10 at 0.01mg kg-1, and 10% dextrose as a control group. The results showed that there are minimum changes in heart and respiratory rate, blood gases, blood pressure, and body temperature after subarachnoid administration of hyperbaric opioids in horses. No sedation and nor motor impairment or behavioral changes occur.

scholarly journals Ultrasound-guided assessment of diaphragmatic thickness as an indicator of successful extubation in mechanically ventilated cancer patients

2019 ◽  
pp. 175-185
Author(s):  
Ahmed M. Soliman ◽  
Mohga A. Samy ◽  
Ashraf M. Heikal ◽  
Mohamed A. El Ramely ◽  
Tamer A. Kotb
Keyword(s):  
Mechanical Ventilation ◽  
Blood Gases ◽  
Arterial Blood Gases ◽  
Ultrasound Guided ◽  
Diaphragm Thickness ◽  
Percent Change ◽  
Rapid Shallow Breathing Index ◽  
Arterial Blood ◽  
Shallow Breathing ◽  
Successful Extubation

Objective: The study aimed to assess diaphragmatic thickness measurement by B-mode ultrasound for prediction of extubation and proper timing of weaning from mechanical ventilation in cancer patients admitted to the intensive care unit after major surgery.Methodology: A prospective, longitudinal study conducted at Surgical ICU, National Cancer Institute, Cairo University, Cairo. Fifty patients were recruited during the immediate postoperative period after major elective cancer surgery who needed mechanical ventilation (MV). Patients were enrolled when judged to be eligible for a test of weaning from MV according to clinical and arterial blood gases (ABG) criteria. The patient was assessed for weaning according to rapid shallow breathing index (RSBI) and ultrasound guided measurements of diaphragmatic thickness (tdi) during inspiration and expiration. The percent change in tdi between end-expiration and end-inspiration (Δtdi%) was calculated. The primary outcome measure was diagnostic accuracy of tdi and Δtdi% to predict weaning compared to ABG analysis (the gold standard for weaning).Results: After 48 hours, 13 patients were weaned according to ABG criteria. Kappa value (agreement) between RSBI and ABG was 0.974. Kappa between both tdi and Δtdi% and the ABG criteria was 0.891. The values differed slightly in patients tested after 72 hours. Sensitivity of a cut off level of tdi of 2 mm was 84.6% and 83.3% after 48 and 72 hours of MV, respectively. Sensitivity of Δtdi% of 20% was clearly higher after 72 hours (95.8%). Using ROC curves, Δtdi% of > 29.5% was also more sensitive after 72 hours.Conclusion: Ultrasound estimation of diaphragm function is a promising tool to help clinicians to judge weaning readiness in patients on mechanical ventilation following major cancer surgery. Diaphragm thickness and its change between end-expiration and end-inspiration showed high degree of agreement with arterial blood gases for predicting weaning readiness.Abbreviations: RSBI: Rapid shallow breathing index, MV: mechanical ventilation, tdi: diaphragm thickness, Δtdi%: percent change in tdi between end-expiration and end-inspiration, PPV: positive predictive value, NPV: negative predictive value, kappa: measure of agreement, NCI: National Cancer Institute, VIDD: ventilator-induced diaphragmatic dysfunctionCitation: Soliman AM, Samy MA, Heikal AM, El Ramely MA, Kotb TA. Ultrasoundguidedassessment of diaphragmatic thickness as an indicator of successful extubation. Anaesth pain & intensive care 2019;23(2):178-185

scholarly journals The Effect of Endotracheal Suctioning on Arterial Blood Gases in Patients Receiving Mechanical Ventilation: A Before-After Open Clinical Trial

2008 ◽  
Vol 6 (1) ◽  
pp. 19-26
Author(s):  
Mahmood Kohan ◽  
Ebrahim Rahimi ◽  
Hamid Mommtahan ◽  
Nahid Mohammad Taheri ◽  
Saeed Sobhanian ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Mechanical Ventilation ◽  
Blood Gases ◽  
Arterial Blood Gases ◽  
Endotracheal Suctioning ◽  
Arterial Blood

Vaporized Perfluorohexane Attenuates Ventilator-induced Lung Injury in Isolated, Perfused Rabbit Lungs

2005 ◽  
Vol 102 (3) ◽  
pp. 597-605 ◽  
Author(s):  
Marcelo Gama de Abreu ◽  
Beate Wilmink ◽  
Matthias Hübler ◽  
Thea Koch
Keyword(s):  
Lung Injury ◽  
Therapy Group ◽  
Peak Inspiratory Pressure ◽  
Thromboxane B2 ◽  
Inspiratory Pressure ◽  
Control Group ◽  
Positive End Expiratory Pressure ◽  
Lung Weight ◽  
Ventilator Induced Lung Injury ◽  
Perfusate Flow

Background The authors tested the hypothesis that administration of vaporized perfluorohexane may attenuate ventilator-induced lung injury. Methods In isolated, perfused rabbit lungs, airway pressure-versus-time curves were recorded. At baseline, peak inspiratory pressure and positive end-expiratory pressure of mechanically ventilated lungs were set to obtain straight pressure-versus-time curves in both the lower and upper ranges, which are associated with less collapse and overdistension, respectively. After that, peak inspiratory pressure and positive end-expiratory pressure were set at 30 cm H2O and 0, respectively, and animals were randomly assigned to one of two groups: (1) simultaneous administration of 14% perfluorohexane vapor in room air (n = 7) and (2) control group-ventilation with room air (n = 7). After 20 min of cycling collapse and overdistension, tidal volume and positive end-expiratory pressure were set back to baseline levels, administration of perfluorohexane in the therapy group was stopped, and mechanical ventilation was continued for up to 60 min. Lung weight, mean pulmonary artery pressure, and concentration of thromboxane B2 in the perfusate were measured. In addition, the distribution of pulmonary perfusate flow was assessed by using fluorescent-labeled microspheres. Results Significantly higher peak inspiratory values developed in control lungs than in lungs treated with perfluorohexane. In addition, upper ranges of pressure-versus-time curves were closer to straight lines in the perfluorohexane group. Lung weight, mean pulmonary arterial pressure, and release of thromboxane B2 were significantly higher in controls than in perfluorohexane-treated lungs. Also, redistribution of pulmonary perfusate flow from caudal to cranial zones was less important in the treatment group. Conclusion The authors conclude that the administration of perfluorohexane vapor attenuates the development of ventilator-induced lung injury in isolated, perfused rabbit lungs.

Influence of respiratory stress and hypertension upon the blood-brain barrier

1980 ◽  
Vol 53 (5) ◽  
pp. 666-673 ◽  
Author(s):  
Joe Sam Robinson ◽  
Robert A. Moody
Keyword(s):  
Blood Brain Barrier ◽  
Blood Gases ◽  
Brain Barrier ◽  
Control Group ◽  
Arterial Blood Gases ◽  
White Rats ◽  
Arterial Blood ◽  
Blood Brain ◽  
Bbb Permeability ◽  
Bbb Opening

✓ The effects of acute hypertension and respiratory stress induced by Aramine (metaraminol bitartrate) upon blood-brain barrier (BBB) permeability to horseradish peroxidase (HRP) were studied in adult inbred white rats. The BBB permeability was quantitated by slicing the brain of each animal into 500-µ thick sections, incubating the sections using the Reese-Karnovsky method, and counting all observed HRP perivascular exudates. No evidence of BBB compromise or significant elevation of blood pressure (BP) was observed in the following experimental groups: 1) control group of five animals; 2) hyperventilated group of five animals (final mean arterial blood gases: pO2, 104.2 mm Hg; pCO2, 24.8 mm Hg; pH, 7.53); 3) anoxicstress group of five animals (final mean arterial blood gases: pCO2, 31.4 mm Hg; pCO2, 58.2 mm Hg; pH, 7.21). However, in a group of 15 animals subjected to anoxic stress followed by hyperventilation, in addition to extreme changes in the levels of arterial blood gases, a significant BP increase occurred (mean BP increase per second, 3.43 ± 0.25 mm Hg; final mean BP, 163.3 ± 3.18 mm Hg); as well as significant BBB opening (mean number of HRP exudates per animal, 12.2 ± 0.85). Likewise, a final group of 10 animals given intravenous Aramine displayed a significant systemic BP elevation (mean BP increase per second, 6.9 ± 0.38 mm Hg; final mean BP, 165.8 ± 3.16 mm Hg), accompanied by BBB opening (mean number of exudates per animal, 51.5 ± 5.95). The variable most strongly associated with the degree of barrier opening was the rate of BP rise (correlation coefficient = + 0.84).

Effects of expiratory ribcage compression before endotracheal suctioning on arterial blood gases in patients receiving mechanical ventilation

2014 ◽  
Vol 19 (5) ◽  
pp. 255-261 ◽  
Author(s):  
Mahmoud Kohan ◽  
Morteza Rezaei-Adaryani ◽  
Akram Najaf-Yarandi ◽  
Fatemeh Hoseini ◽  
Nahid Mohammad-Taheri
Keyword(s):  
Mechanical Ventilation ◽  
Blood Gases ◽  
Arterial Blood Gases ◽  
Endotracheal Suctioning ◽  
Arterial Blood

Quantifying the potential of infant bedding to limit CO2 dispersal and factors affecting rebreathing in bedding

1995 ◽  
Vol 78 (2) ◽  
pp. 740-745 ◽  
Author(s):  
J. S. Kemp ◽  
B. T. Thach
Keyword(s):  
Mechanical Model ◽  
Rabbit Model ◽  
Blood Gases ◽  
Arterial Blood Gases ◽  
Arterial Pco2 ◽  
Factors Affecting ◽  
Model Studies ◽  
Quantitative Studies ◽  
Arterial Blood ◽  
Independent Effects

Rebreathing may impair ventilation and lead to sudden death among sleeping infants. To estimate the potential for rebreathing imposed by an infant's sleep microenvironment, we developed a mechanical model to assess the rate of CO2 dispersal away from an infant's face. We compared the mechanical model results with changes in arterial blood gases of rabbits. The rabbits breathed into the same microenvironments used for the model studies. In the rabbits, rebreathing (documented by capnometry) caused hypercarbia and in some cases death. The mechanical model consisted of the mannequin head positioned as in the rabbit studies and connected to a 100-ml syringe filled with CO2. CO2 was washed out of the system using 30-ml “breaths” (rate = 15/min). The half times (t1/2) for CO2 dispersal served to quantify the rebreathing potential of 16 items of bedding. The t1/2 values correlated with increments in the rabbits' arterial PCO2 (r = 0.789). The threshold for the increase in the rabbits' arterial PCO2 corresponded to t1/2 values of > or = 18.7 s; the 90% point for lethality in the rabbit model was 28.1 s. The mechanical model was also used to show the independent effects of softness and porosity of bedding on its rebreathing potential. By describing the potential for rebreathing within bedding, the mechanical model should be useful in future quantitative studies of infants' respiratory adaptation to sleep microenvironments.

scholarly journals Rapid Onset of Specific Diaphragm Weakness in a Healthy Murine Model of Ventilator-induced Diaphragmatic Dysfunction

2012 ◽  
Vol 117 (3) ◽  
pp. 560-567 ◽  
Author(s):  
Segolene Mrozek ◽  
Boris Jung ◽  
Basil J. Petrof ◽  
Marion Pauly ◽  
Stephanie Roberge ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Blood Gases ◽  
Hemodynamic Parameters ◽  
Arterial Blood Gases ◽  
Diaphragmatic Dysfunction ◽  
Arterial Blood ◽  
Controlled Mechanical Ventilation ◽  
Mechanical Ventilation Group

Background Controlled mechanical ventilation is associated with ventilator-induced diaphragmatic dysfunction, which impedes weaning from mechanical ventilation. To design future clinical trials in humans, a better understanding of the molecular mechanisms using knockout models, which exist only in the mouse, is needed. The aims of this study were to ascertain the feasibility of developing a murine model of ventilator-induced diaphragmatic dysfunction and to determine whether atrophy, sarcolemmal injury, and the main proteolysis systems are activated under these conditions. Methods Healthy adult male C57/BL6 mice were assigned to three groups: (1) mechanical ventilation with end-expiratory positive pressure of 2-4 cm H2O for 6 h (n=6), (2) spontaneous breathing with continuous positive airway pressure of 2-4 cm H2O for 6 h (n=6), and (3) controls with no specific intervention (n=6). Airway pressure and hemodynamic parameters were monitored. Upon euthanasia, arterial blood gases and isometric contractile properties of the diaphragm and extensor digitorum longus were evaluated. Histology and immunoblotting for the main proteolysis pathways were performed. Results Hemodynamic parameters and arterial blood gases were comparable between groups and within normal physiologic ranges. Diaphragmatic but not extensor digitorum longus force production declined in the mechanical ventilation group (maximal force decreased by approximately 40%) compared with the control and continuous positive airway pressure groups. No histologic difference was found between groups. In opposition with the calpains, caspase 3 was activated in the mechanical ventilation group. Conclusion Controlled mechanical ventilation for 6 h in the mouse is associated with significant diaphragmatic but not limb muscle weakness without atrophy or sarcolemmal injury and activates proteolysis.

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